Pith. sign in

REVIEW 1 major objections 6 minor 101 references

Current-current operator contribution to the decay matrix in $B$-meson mixing at next-to-next-to-leading order of QCD

T0 review · 1 major / 6 minor · reviewed 2026-08-07 · deepseek-v4-flash

Pith's one-line read The paper reports the three-loop (NNLO) QCD matching coefficients for the current-current operator contribution to the $B_q$-$\bar B_q$ decay matrix with full dependence on $z=m_c^2/m_b^2$, and uses them to predict…

desk verdict A solid, internally well-checked three-loop matching calculation that completes the NNLO current-current program; the residual 1/N_c evanescent-scheme issue is a real gap but not a demonstrated numerical flaw. read the letter →

arxiv 2505.22740 v1 pith:U2ZCOGZF submitted 2025-05-28 hep-ph

classification hep-ph
keywords BmesonmixingdecaywidthdifferenceNNLOQCDthree-loopcalculationFierzsymmetryevanescentoperatorsheavyquarkexpansionCPasymmetryinflavour-specificdecays
verification ladder T0 review T1 audit T2 compute T3 formal

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The reading

This paper claims that the three-loop (NNLO) QCD corrections induced by two current-current operators to the off-diagonal decay matrix $\Gamma_{12}$ in $B_q$-$\bar B_q$ mixing have been computed, with full dependence on $z=m_c^2/m_b^2$ expressed as a semi-analytic expansion to order $z^{10}$ (and to $z^{50}$ for the leading terms). The computation required constructing the $|\Delta B|=2$ effective theory so that Fierz symmetry is preserved in $D\neq 4$ dimensions, which fixes the evanescent-operator definitions that enter the renormalisation. The new corrections stabilise the renormalisation-scale dependence and reduce the perturbative uncertainty of the leading $1/m_b$ term in $\Delta\Gamma_s$ to the level of the current experimental error. A sympathetic reader would care because $\Gamma_{12}$ controls the observable width differences and flavour-specific CP asymmetries, and the updated Standard Model predictions sharpen tests of $B$-mixing that do not rely on a global CKM fit.

What carries the argument

The load-bearing object is the Fierz-symmetric set of evanescent operators in the $|\Delta B|=2$ theory: operators with extra Dirac matrices (first to fourth generation) that vanish in four dimensions but are needed to renormalise the physical operators $Q$, $Q_S$, and $\tilde Q_S$ in $D\neq 4$. Their $O(\epsilon)$ and $O(\epsilon^2)$ coefficients are fixed by three conditions: equality of renormalised physical matrix elements with their Fierz transforms at one- and two-loop order, flavour-number independence of the operator definitions, and correct large-$N_c$ counting. The second-generation coefficients are pinned down only up to a solution space, and the paper verifies that the leading $O(N_c^2)$ term of the renormalised physical matrix elements is independent of the remaining constants. A second load-bearing element is the finite renormalisation of $R_0=\frac12 Q+Q_S+\tilde Q_S$, whose matrix element must be $1/m_b$ suppressed; the constants $\alpha_1,\alpha_2$ are extracted at two loops by separating UV from IR divergences with a gluon mass. These two elements make the matching coefficients IR-finite order by order in $\alpha_s$ and compatible with four-dimensional lattice matrix elements.

What would settle it

Take the generic evanescent-operator solution of Appendix D instead of the specific choice in Eqs. (31)-(34), recompute the subleading $1/N_c$ terms of the renormalised physical matrix elements at two loops, and check whether the NNLO matching coefficients change by more than the quoted scale uncertainty; a larger shift would show that the Fierz-symmetry conditions do not uniquely fix the scheme. On the experimental side, a future measurement of $\Delta\Gamma_s$ with uncertainty below about $0.005\,\text{ps}^{-1}$ that falls outside $0.077\pm0.016\,\text{ps}^{-1}$ would rule out the Standard Model prediction presented here.

Watch

Extended reading notes

Core claim

The central claim is that the three-loop (NNLO) QCD matching coefficients for the contribution of two current-current operators to $\Gamma^q_{12}$ are now known with full dependence on $z=m_c^2/m_b^2$, provided as a semi-analytic expansion to order $z^{10}$ (and to $z^{50}$ for the leading terms). The calculation is performed in a $|\Delta B|=2$ effective theory whose evanescent operators are fixed so that Fierz symmetry holds in $D\neq 4$ dimensions: the renormalised matrix elements of physical operators equal those of their Fierz transforms at one- and two-loop level, the operator definitions do not depend on the number of quark flavours, and the large-$N_c$ limit is correctly reproduced. With the finite renormalisation of $R_0$ enforcing its $1/m_b$ suppression, the matching yields finite NNLO Wilson coefficients. Combined with lattice bag parameters and $1/m_b$ matrix elements, these coefficients give $\Delta\Gamma_s=(0.077\pm0.016)\,\text{ps}^{-1}$, $\Delta\Gamma_d=(0.00211\pm0.00045)\,\text{ps}^{-1}$, $a_{\rm fs}^s=(2.28\pm0.14)\times10^{-5}$, and $a_{\rm fs}^d=-(5.21\pm0.32)\times10^{-4}$, with the uncertainty of $\Delta\Gamma_s$ dominated by the sub-leading terms of the $1/m_b$ expansion.

Load-bearing premise

The result depends on the assumption that the chosen Fierz-symmetry-preserving renormalisation scheme is the one that matches the four-dimensional lattice operator basis: if another admissible choice of the remaining evanescent-operator constants altered the subleading colour-suppressed terms of the NNLO matching coefficients, the quoted prediction would shift at order $\alpha_s^2$ by more than the stated uncertainty.

Editorial extensions

If this is right

  • The perturbative uncertainty of the leading $1/m_b$ term in $\Delta\Gamma_s$ drops to the level of the current experimental error, so further progress on $\Delta\Gamma_s$ now hinges mostly on the matrix elements of the $1/m_b$-suppressed operators.
  • Because the ratio $\Delta\Gamma_q/\Delta M_q$ is almost independent of $|V_{cb}|$, the NNLO prediction sharpens a probe of new physics that does not require resolving the $|V_{cb}|$ puzzle.
  • The NNLO corrections reduce the renormalisation-scale variation of $\Delta\Gamma_s/\Delta M_s$ by roughly a factor of two in both the MS and PS schemes (about 15% and 17% in the $[2.1,8.4]$ GeV interval, versus 33% and 26% at NLO).
  • The Standard Model values $a_{\rm fs}^s=(2.28\pm0.14)\times10^{-5}$ and $a_{\rm fs}^d=-(5.21\pm0.32)\times10^{-4}$ are now stable under scale variation, making a future measurement of $a_{\rm fs}^d$ a direct test of the CKM-apex constraint from $B$-mixing observables alone.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

  • The same Fierz-symmetry construction could be applied to the uncalculated penguin-operator contributions at NNLO; the paper estimates their numerical effect at the central scale is small, but including them may further stabilise the renormalisation-scale dependence.
  • The solution-space freedom in the second-generation evanescent operators (Eqs. (31)-(34) versus the generic solution in Appendix D) offers a concrete test: recomputing the matching coefficients with different admissible constants would reveal whether the subleading $1/N_c$ terms are truly scheme-independent, as the leading $O(N_c^2)$ term is claimed to be.
  • Because the semi-analytic expansion to $z^{10}$ is effectively exact for the physical charm-to-bottom mass ratio, the practical bottleneck for $\Delta\Gamma_s$ is the lattice determination of the dimension-7 operator matrix elements; improving those inputs will translate directly into a more precise Standard Model prediction.
Share X Bluesky LinkedIn Reddit HN

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, and a circularity audit.

Referee Report

1 major / 6 minor

Summary. This paper presents the first complete three-loop (NNLO) QCD calculation of the current-current operator contribution to the off-diagonal decay matrix element Γ_12 in B_q–\bar B_q mixing, retaining the full dependence on z = m_c^2/m_b^2 through a semi-analytic expansion of the three-loop master integrals. The authors construct a Fierz-symmetric renormalisation scheme for the |ΔB|=2 effective theory, compute the matching coefficients H^(2) and \tilde H_S^(2), and perform a phenomenological analysis of ΔΓ_q, ΔΓ_q/ΔM_q, and a_fs^q for q = d, s. Their final result is ΔΓ_s = (0.077 ± 0.016) ps^-1, with the scale uncertainty of the leading 1/m_b term reduced to a level comparable to the current experimental error; the remaining uncertainty is dominated by the 1/m_b-suppressed hadronic matrix elements.

Significance. If the result stands, this is a substantial step forward in B-meson mixing phenomenology. The NNLO correction stabilises the renormalisation-scale dependence of the leading-power term, and the deep semi-analytic expansion in z makes the result usable over the full physical range. The paper is distinguished by strong internal cross-checks: two independent automated setups, reproduction of the NLO benchmark of Ref. [11] and the fermionic NNLO benchmark of Ref. [17], cancellation of IR poles in the matching (Eq. (67)), gauge-parameter independence of the α_i constants, and analytic master integrals checked with pySecDec. The authors also provide computer-readable ancillary files for the renormalisation constants and matching coefficients, which is a valuable resource. The principal reservation is the unverified independence of the physical NNLO matching coefficients from the residual freedom in the second-generation evanescent operator definitions at subleading order in 1/N_c.

major comments (1)
  1. [Section 2.3, Eqs. (31)–(34), Appendix D] The construction of the Fierz-symmetric renormalisation scheme in Section 2.3 leaves a solution space for the second-generation evanescent coefficients; the paper selects one member of this space (Eqs. (31)–(34)) after imposing conditions 1–3. Appendix D states that only the leading O(N_c^2) term of the renormalised physical matrix elements is independent of the remaining undetermined constant. The NNLO matching coefficients H^(2) and \tilde H_S^(2) that enter Eq. (84) are computed in this chosen scheme, and the paper does not demonstrate that the subleading 1/N_c parts of these coefficients are also independent of the arbitrary constants (e.g., k and \tilde k set to zero in Eq. (33)). For N_c = 3 the subleading terms are not parametrically negligible, and the lattice bag parameters used in Eq. (77) are four-dimensional quantities that cannot cancel a perturbative scheme dependence of the Wilson coefficients at order α_s^2. The authors should either prove the full independence of the physical matching coefficients from all allowed evanescent constants, or quantify the numerical shift in ΔΓ_s obtained by varying those constants within the allowed solution space. Without this check, the central claim that the NNLO perturbative uncertainty of the leading 1/m_b term is reduced to the experimental level is not fully established.
minor comments (6)
  1. [Abstract] The phrase "The calculated NNLO correction reduce" contains a subject-verb disagreement; it should be "The calculated NNLO correction reduces".
  2. [Table 2] The entry for f_Bd is given as "0.1905 ± 0.0013 MeV"; to match the f_Bs entry and the text, the unit should be GeV.
  3. [Eq. (54)] In the expression for α_2^(2), the N_H term contains an extra closing parenthesis after the bracket; please correct the typo.
  4. [Appendix C] The sentence "In Eqs. 107 we set mb to unity" should read "In Eqs. (107) we set mb to unity".
  5. [Abstract and Section 4] The abstract describes the result as having "full dependence" on the quark masses; since the computation is a semi-analytic expansion in z up to order z^10 (with z^50 for some leading terms), I suggest adding the word "semi-analytic" to the abstract to avoid overstatement.
  6. [Section 2.3] The statement that the O(ϵ) terms of the third- and fourth-generation evanescent operators "can be checked" to drop out of the physical matching coefficients is asserted but not demonstrated in the text; please provide the check or an explicit reference.

Circularity Check

0 steps flagged · score 0.0 of 10

No significant circularity: the NNLO matching coefficients are computed from first principles and anchored to external lattice and experimental benchmarks.

full rationale

The central object, the NNLO matching coefficients H^(2) and \tilde H_S^(2) for the current-current operators, is obtained by a genuine three-loop QCD matching calculation (Sections 2.7, 3 and 4) with two independent computational setups and IR-pole-cancellation checks, not by fitting to ΔΓ. The non-perturbative inputs (bag parameters and 1/m_b matrix elements) come from external lattice QCD (Refs. [56,79]) and sum rules, and the final ΔΓ_s prediction is compared with LHCb/HFLAV measurements; no quantity that is predicted is also used as an input. The authors' own earlier results (Refs. [15,16,20,21]) appear as intermediate cross-checks that are reproduced, not as the source of the new coefficients; the Fierz-symmetric evanescent-operator construction in Section 2.3 is a renormalisation-scheme convention rather than a derived physical constraint. The only caveat, already acknowledged in Appendix D, is that the residual freedom in the second-generation evanescent coefficients is checked for the leading N_c^2 term but not for subleading 1/N_c terms; this is a potential scheme-ambiguity or correctness risk for N_c=3, not a circularity, because the physical matrix-element combination is defined to be scheme independent and the paper does not redefine the prediction to match the data.

Assumptions & free parameters 3 free parameters · 5 assumptions · 0 invented entities

The calculation has no free parameters fitted to the target observables: masses, CKM elements, bag parameters and decay constants come from external measurements, lattice QCD and global fits. The genuinely paper-specific choices are the evanescent operator scheme (one solution from a solution space), the central scale 4.2 GeV, and the gluon-mass regulator; all three are claimed to cancel or are varied to estimate uncertainty. The dominant unstated input risk is the set of dimension-7 lattice matrix elements, which dominate the final error. No new entities are invented; the evanescent operators and the gluon-mass regulator are computational devices without on-shell physical content.

free parameters (3)
  • Evanescent operator scheme constants (c, d, h, k and Fierz-basis counterparts) = Chosen solution: c = c2 = c-tilde = d = d2 = d-tilde = d-tilde2 = 0, k = k-tilde = 0; others as in Eq. (34)
    Scheme-defining constants chosen by hand to realise Fierz-symmetry conditions 1 to 3. They are claimed to cancel in physical observables; independence is verified only for the leading N_c^2 term, so they carry residual scheme-selection risk.
  • Central renormalisation scale set (mu1 = muc = mub) = 4.2 GeV, varied over 2.1 to 8.4 GeV
    Standard scale-variation prescription for estimating perturbative uncertainty; the central value is chosen of order m_b and is not fitted to data.
  • Gluon-mass IR regulator for the alpha1, alpha2 extraction = mg inserted in gluon and ghost propagators; several variants tested
    Technical regulator separating UV from IR in the R0 matrix elements. The paper shows alpha1 and alpha2 are invariant across the variants and independent of the gauge parameter, which is the required check for this to drop out.
assumptions (5)
  • domain assumption The absorptive part of the double-insertion of two |Delta B| = 1 Hamiltonians (Eq. (11)) admits an OPE in local |Delta B| = 2 operators, i.e. the heavy quark expansion for Gamma_12 is valid at leading power, with 1/m_b terms captured by dimension-7 operators.
    Invoked in Section 2 before Eq. (56). The power-suppression of <R0> beyond tree level is restored by the finite renormalisation constants alpha1 and alpha2 of Section 2.6.
  • ad hoc to paper Evanescent operators with the chosen O(epsilon) and O(epsilon^2) coefficients, including arbitrary O(epsilon) terms for the third and fourth generations, do not contribute to the physical matching coefficients.
    Assumed structurally in Section 2.3 and stated as checkable in Appendix D; only the leading O(N_c^2) term of the renormalised physical matrix elements is explicitly verified.
  • domain assumption Lattice QCD matrix elements of the dimension-7 operators (Refs. [56, 79]) are correct and combine with the LO Wilson coefficients; flavour SU(3) breaking is neglected in <Bd|R0|Bd-bar> (Eq. (79)).
    Used in Section 5.1; these inputs dominate the final error of Delta_Gamma_s and Delta_Gamma_d, so an error here would shift the central predictions beyond the quoted uncertainty.
  • domain assumption Truncation of the semi-analytic expansion at z^10 (z^50 for the leading terms) is numerically equivalent to an exact evaluation over the relevant mass range.
    Supported by the stated estimate that the highest included term contributes below 10^-6 to the (alpha_s/4pi)^2 coefficient at the largest z in the scale variation (Section 3); the z^0 and z^1 terms are cross-checked analytically in Appendix C.
  • domain assumption External Standard Model inputs (Delta B = 1 Wilson coefficients from Ref. [7], CKM parameters from Ref. [62], quark masses, bag parameters and decay constants of Table 2) are correct and carry the quoted uncertainties.
    Used throughout Section 5 and propagated in quadrature; none of these inputs is fitted in this paper.

how reviews work

0 comments
Cite this review

Pith. "Pith review of Current-current operator contribution to the decay matrix in $B$-meson mixing at next-to-next-to-leading order of QCD." pith.science (2026). https://pith.science/paper/U2ZCOGZF

@misc{pith2026250522740,
  author       = {Pith},
  title        = {Pith review of: Current-current operator contribution to the decay matrix in $B$-meson mixing at next-to-next-to-leading order of QCD},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/U2ZCOGZF}},
  note         = {Machine review of arXiv:2505.22740}
}
abstract

We compute next-to-next-to-leading order perturbative corrections to the decay width difference of mass eigenstates and the charge-parity asymmetry $a_{\rm fs}$ in flavour-specific decays of neutral $B$ mesons. In our calculation we take into account the full dependence on the charm and bottom quark masses for the current-current operator contributions up to three-loop order. Special emphasis is put on the proper construction of the so-called $|\Delta B|=2$ theory such that Fierz symmetry is preserved. We provide updated phenomenological predictions, for $\Delta\Gamma$, $\Delta\Gamma/\Delta M$ and $a_{\rm fs}$ for the $B_d$ and $B_s$ system, including a detailed analysis of the uncertainties of our predictions. The calculated NNLO correction reduce the perturbative uncertainty of the leading term of the $1/m_b$ expansion of the width difference $\dg_s$ in the $B_s$ system to the level of the current experimental error. The uncertainty of our prediction $\dg_s=({0.077}\pm 0.016)\,\mbox{ps}^{-1}$ is dominated by the sub-leading term of this expansion. We further illustrate how better future measurements of $\dg_d$ and $a_{\rm fs}^d$ will help to gain a better understanding of $B_d$-$\bar B_d$ mixing.

Figures

Figures reproduced from arXiv: 2505.22740 by the authors.

Figure 1
Figure 1. Left: box diagram describing Bq−B¯ q mixing with q = d or s to leading order in QCD. Right: constraints from the three B−B¯ mixing observables ∆Md/∆Ms ∝ R2 t , aCP (Bd(t) → J/ψKS) ∝ sin(2β), and a d fs ∝ (sin β)/Rt on the apex (¯ρ, η¯) of the CKM unitarity triangle. a s,exp fs = −0.0006 ± 0.0028 , [2] (6) ∆M exp d = (0.5065 ± 0.0019) ps−1 , [2] (7) ∆Γexp d = (0.7 ± 6.6) · 10−3 ps−1 , [2] (8) a d,exp fs = −0.0021 ± 0… view at source ↗
Figure 2
Figure 2. One- and two-loop Feynman diagrams needed for the calculation of [PITH_FULL_IMAGE:figures/full_fig_p019_2.png] view at source ↗
Figure 3
Figure 3. Two-loop master integrals where all lines represent scalar propagators. Solid [PITH_FULL_IMAGE:figures/full_fig_p020_3.png] view at source ↗
Figures from the paper (7 more)
Figure 4
Figure 4. Figure 4: Renormalisation scale dependence at LO (short dashes), NLO (long dashes) [PITH_FULL_IMAGE:figures/full_fig_p033_4.png]
Figure 5
Figure 5. Figure 5: Renormalisation scale dependence at LO (short dashes), NLO (long dashes) [PITH_FULL_IMAGE:figures/full_fig_p036_5.png]
Figure 6
Figure 6. Figure 6: ∆Γq versus ∆Mq for the Bs (left) and Bd (right) schemes. The different hori￾zontal and vertical coloured bands refer to different input values for |Vcb|. The bands for ∆Γs are obtained from a direct calculation according to Eq. (3) using the values for λ s t as given i…
Figure 7
Figure 7. Figure 7: Renormalisation scale dependence at LO (short dashes), NLO (long dashes) [PITH_FULL_IMAGE:figures/full_fig_p041_7.png]
Figure 8
Figure 8. Figure 8: Constraints on the apex of the CKM triangle in the (¯ρ [PITH_FULL_IMAGE:figures/full_fig_p043_8.png]
Figure 9
Figure 9. Figure 9: One- and two-loop master integrals. Solid and dotted lines denote massive [PITH_FULL_IMAGE:figures/full_fig_p047_9.png]
Figure 10
Figure 10. Figure 10: Three-loop master integrals arising from the ∆ [PITH_FULL_IMAGE:figures/full_fig_p048_10.png]

Discussion (0). Continue with ORCID to comment.

Reference graph

Works this paper leans on

101 extracted references · 10 canonical work pages

  1. [20]

    Gerlach, U

    M. Gerlach, U. Nierste, V. Shtabovenko and M. Steinhauser, Width Difference in the B- ¯B System at Next-to-Next-to-Leading Order of QCD , Phys. Rev. Lett. 129 (2022) 102001 [ 2205.07907]

  2. [11]

    Beneke, G

    M. Beneke, G. Buchalla, C. Greub, A. Lenz and U. Nierste, Next-to-leading order QCD corrections to the lifetime difference of Bs mesons, Phys. Lett. B 459 (1999) 631 [hep-ph/9808385]

  3. [17]

    Asatrian, A

    H.M. Asatrian, A. Hovhannisyan, U. Nierste and A. Yeghiazaryan, Towards next-to-next-to-leading-log accuracy for the width difference in the Bs − ¯Bs system: fermionic contributions to order (mc/mb)0 and (mc/mb)1, JHEP 10 (2017) 191 [1709.02160]

  4. [1]

    18 (2022) 1 [ 2104.04421]

    LHCb collaboration, Precise determination of the B0 s –B 0 s oscillation frequency, Nature Phys. 18 (2022) 1 [ 2104.04421]

  5. [2]

    HFLA Vcollaboration, Averages of b-hadron, c-hadron, and τ -lepton properties as of 2021 , Phys. Rev. D 107 (2023) 052008 [ 2206.07501]

  6. [3]

    Buras and P.H

    A.J. Buras and P.H. Weisz, QCD Nonleading Corrections to Weak Decays in Dimensional Regularization and ’t Hooft-Veltman Schemes , Nucl. Phys. B 333 (1990) 66

  7. [4]

    Buras, M

    A.J. Buras, M. Jamin, M.E. Lautenbacher and P.H. Weisz, Effective Hamiltonians for ∆S = 1 and ∆B = 1 nonleptonic decays beyond the leading logarithmic approximation, Nucl. Phys. B 370 (1992) 69

  8. [5]

    Buras, M

    A.J. Buras, M. Jamin, M.E. Lautenbacher and P.H. Weisz, Two loop anomalous dimension matrix for ∆S = 1 weak nonleptonic decays I: O(α2 s), Nucl. Phys. B 400 (1993) 37 [ hep-ph/9211304]

Show all 101 references
  1. [6]

    Gambino, M

    P. Gambino, M. Gorbahn and U. Haisch, Anomalous Dimension Matrix for Radiative and Rare Semileptonic B Decays Up to Three Loops , Nucl. Phys. B 673 (2003) 238 [ hep-ph/0306079]

  2. [7]

    Gorbahn and U

    M. Gorbahn and U. Haisch, Effective Hamiltonian for non-leptonic |∆F | = 1 decays at NNLO in QCD , Nucl. Phys. B 713 (2005) 291 [ hep-ph/0411071]

  3. [8]

    Gorbahn, U

    M. Gorbahn, U. Haisch and M. Misiak, Three-loop mixing of dipole operators , Phys. Rev. Lett. 95 (2005) 102004 [ hep-ph/0504194]

  4. [9]

    Buras, W

    A.J. Buras, W. Slominski and H. Steger, B0 − ¯B0 Mixing, CP Violation and the B Meson Decay, Nucl. Phys. B 245 (1984) 369

  5. [10]

    Beneke, G

    M. Beneke, G. Buchalla and I. Dunietz, Width Difference in the Bs − ¯Bs System, Phys. Rev. D 54 (1996) 4419 [ hep-ph/9605259]. 52

  6. [12]

    Beneke, G

    M. Beneke, G. Buchalla, A. Lenz and U. Nierste, CP Asymmetry in Flavor Specific B Decays beyond Leading Logarithms, Phys. Lett. B 576 (2003) 173 [hep-ph/0307344]

  7. [13]

    Ciuchini, E

    M. Ciuchini, E. Franco, V. Lubicz and F. Mescia, Next-to-leading order QCD corrections to spectator effects in lifetimes of beauty hadrons , Nucl. Phys. B 625 (2002) 211 [ hep-ph/0110375]

  8. [14]

    Lenz and U

    A. Lenz and U. Nierste, Theoretical update of Bs − ¯Bs mixing, JHEP 06 (2007) 072 [hep-ph/0612167]

  9. [15]

    Gerlach, U

    M. Gerlach, U. Nierste, V. Shtabovenko and M. Steinhauser, Two-loop QCD penguin contribution to the width difference in B s−Bs mixing, JHEP 07 (2021) 043 [2106.05979]

  10. [16]

    Gerlach, U

    M. Gerlach, U. Nierste, V. Shtabovenko and M. Steinhauser, The width difference in B − ¯B mixing at order αs and beyond, JHEP 04 (2022) 006 [ 2202.12305]

  11. [18]

    Asatrian, H.H

    H.M. Asatrian, H.H. Asatryan, A. Hovhannisyan, U. Nierste, S. Tumasyan and A. Yeghiazaryan, Penguin contribution to the width difference and CP asymmetry in Bq- ¯Bq mixing at order α2 sNf , Phys. Rev. D 102 (2020) 033007 [ 2006.13227]

  12. [19]

    Hovhannisyan and U

    A. Hovhannisyan and U. Nierste, Addendum to: Towards next-to-next-to-leading-log accuracy for the width difference in the B s−Bs system: fermionic contributions to order (m c/mb)0 and (m c/mb)1, JHEP 06 (2022) 090 [2204.11907]

  13. [21]

    Reeck, V

    P. Reeck, V. Shtabovenko and M. Steinhauser, B meson mixing at NNLO: technical aspects, JHEP 08 (2024) 002 [ 2405.14698]

  14. [22]

    Alonso- ´Alvarez, G

    G. Alonso- ´Alvarez, G. Elor and M. Escudero, Collider signals of baryogenesis and dark matter from B mesons: A roadmap to discovery , Phys. Rev. D 104 (2021) 035028 [2101.02706]. 53

  15. [23]

    Laplace, Z

    S. Laplace, Z. Ligeti, Y. Nir and G. Perez, Implications of the CP asymmetry in semileptonic B decay , Phys. Rev. D 65 (2002) 094040 [ hep-ph/0202010]

  16. [24]

    Chetyrkin, M

    K.G. Chetyrkin, M. Misiak and M. Munz, |∆F | = 1 nonleptonic effective Hamiltonian in a simpler scheme , Nucl. Phys. B 520 (1998) 279 [hep-ph/9711280]

  17. [25]

    Herrlich and U

    S. Herrlich and U. Nierste, Evanescent operators, scheme dependences and double insertions, Nucl. Phys. B 455 (1995) 39 [ hep-ph/9412375]

  18. [26]

    Herrlich and U

    S. Herrlich and U. Nierste, The Complete |∆S| = 2 - Hamiltonian in the next-to-leading order, Nucl. Phys. B 476 (1996) 27 [ hep-ph/9604330]

  19. [27]

    Gorbahn, S

    M. Gorbahn, S. Jager, U. Nierste and S. Trine, The supersymmetric Higgs sector and B − ¯B mixing for large tan β, Phys. Rev. D 84 (2011) 034030 [ 0901.2065]

  20. [28]

    Smirnov, Analytic tools for Feynman integrals , vol

    V.A. Smirnov, Analytic tools for Feynman integrals , vol. 250 (2012), 10.1007/978-3-642-34886-0

  21. [29]

    Fleischer and O.V

    J. Fleischer and O.V. Tarasov, SHELL2: Package for the calculation of two loop on-shell Feynman diagrams in FORM , Comput. Phys. Commun. 71 (1992) 193

  22. [30]

    Ancillary files at: https://www.ttp.kit.edu/preprints/2025/ttp25-016/

  23. [31]

    Nierste, Three Lectures on Meson Mixing and CKM phenomenology , in Helmholz International Summer School on Heavy Quark Physics , pp

    U. Nierste, Three Lectures on Meson Mixing and CKM phenomenology , in Helmholz International Summer School on Heavy Quark Physics , pp. 1–38, 3, 2009 [0904.1869]

  24. [32]

    Nogueira, Abusing QGRAF, Nucl

    P. Nogueira, Abusing QGRAF, Nucl. Instrum. Meth. A 559 (2006) 220

  25. [33]

    Alloul, N.D

    A. Alloul, N.D. Christensen, C. Degrande, C. Duhr and B. Fuks, FeynRules 2.0 - A complete toolbox for tree-level phenomenology , Comput. Phys. Commun. 185 (2014) 2250 [ 1310.1921]

  26. [34]

    Hahn, Generating Feynman diagrams and amplitudes with FeynArts 3 , Comput

    T. Hahn, Generating Feynman diagrams and amplitudes with FeynArts 3 , Comput. Phys. Commun. 140 (2001) 418 [ hep-ph/0012260]

  27. [35]

    Mertig, M

    R. Mertig, M. Bohm and A. Denner, FEYN CALC: Computer algebraic calculation of Feynman amplitudes , Comput. Phys. Commun. 64 (1991) 345

  28. [36]

    Shtabovenko, R

    V. Shtabovenko, R. Mertig and F. Orellana, New Developments in FeynCalc 9.0 , Comput. Phys. Commun. 207 (2016) 432 [ 1601.01167]

  29. [37]

    Shtabovenko, R

    V. Shtabovenko, R. Mertig and F. Orellana, FeynCalc 9.3: New features and improvements, Comput. Phys. Commun. 256 (2020) 107478 [ 2001.04407]

  30. [38]

    Hahn and M

    T. Hahn and M. Perez-Victoria, Automatized one loop calculations in four-dimensions and D-dimensions , Comput. Phys. Commun. 118 (1999) 153 [hep-ph/9807565]. 54

  31. [39]

    Harlander, T

    R. Harlander, T. Seidensticker and M. Steinhauser, Complete corrections of O(ααs) to the decay of the Z boson into bottom quarks , Phys. Lett. B 426 (1998) 125 [hep-ph/9712228]

  32. [40]

    T. Seidensticker, Automatic application of successive asymptotic expansions of Feynman diagrams, in 6th International Workshop on New Computing Techniques in Physics Research: Software Engineering, Artificial Intelligence Neural Nets, Genetic Algorithms, Symbolic Algebra, Auto...

  33. [41]

    Kuipers, T

    J. Kuipers, T. Ueda, J.A.M. Vermaseren and J. Vollinga, FORM version 4.0 , Comput. Phys. Commun. 184 (2013) 1453 [ 1203.6543]

  34. [42]

    Smirnov and F.S

    A.V. Smirnov and F.S. Chukharev, FIRE6: Feynman Integral REduction with modular arithmetic, Comput. Phys. Commun. 247 ˆA (2020) 106877 [ 1901.07808]

  35. [43]

    Lee, LiteRed 1.4: a powerful tool for reduction of multiloop integrals , J

    R.N. Lee, LiteRed 1.4: a powerful tool for reduction of multiloop integrals , J. Phys. Conf. Ser. 523 (2014) 012059 [ 1310.1145]

  36. [44]

    Gerlach, F

    M. Gerlach, F. Herren and M. Lang, tapir: A tool for topologies, amplitudes, partial fraction decomposition and input for reductions , Comput. Phys. Commun. 282 (2023) 108544 [ 2201.05618]

  37. [45]

    Gerlach, Three-loop topology analysis of neutral B-meson mixing with tapir , J

    M. Gerlach, Three-loop topology analysis of neutral B-meson mixing with tapir , J. Phys. Conf. Ser. 2438 (2023) 012156 [ 2205.07483]

  38. [46]

    Maierh¨ ofer, J

    P. Maierh¨ ofer, J. Usovitsch and P. Uwer,Kira—A Feynman integral reduction program, Comput. Phys. Commun. 230 (2018) 99 [ 1705.05610]

  39. [47]

    Klappert, F

    J. Klappert, F. Lange, P. Maierh¨ ofer and J. Usovitsch,Integral reduction with Kira 2.0 and finite field methods , Comput. Phys. Commun. 266 (2021) 108024 [2008.06494]

  40. [48]

    Smirnov and V.A

    A.V. Smirnov and V.A. Smirnov, How to choose master integrals , Nucl. Phys. B 960 (2020) 115213 [ 2002.08042]

  41. [49]

    M. Fael, F. Lange, K. Sch¨ onwald and M. Steinhauser,A semi-analytic method to compute Feynman integrals applied to four-loop corrections to the MS-pole quark mass relation, JHEP 09 (2021) 152 [ 2106.05296]

  42. [50]

    M. Fael, F. Lange, K. Sch¨ onwald and M. Steinhauser,Massive Vector Form Factors to Three Loops, Phys. Rev. Lett. 128 (2022) 172003 [ 2202.05276]

  43. [51]

    M. Fael, F. Lange, K. Sch¨ onwald and M. Steinhauser,Singlet and nonsinglet three-loop massive form factors , Phys. Rev. D 106 (2022) 034029 [ 2207.00027]

  44. [52]

    M. Fael, F. Lange, K. Sch¨ onwald and M. Steinhauser,Massive three-loop form factors: Anomaly contribution , Phys. Rev. D 107 (2023) 094017 [ 2302.00693]. 55

  45. [53]

    Particle Data Groupcollaboration, Review of particle physics , Phys. Rev. D 110 (2024) 030001

  46. [54]

    Charm and bottom quark masses: An update

    K.G. Chetyrkin, J.H. Kuhn, A. Maier, P. Maierhofer, P. Marquard, M. Steinhauser et al., Addendum to “Charm and bottom quark masses: An update” , 1710.04249

  47. [55]

    Chetyrkin, J.H

    K. Chetyrkin, J.H. Kuhn, A. Maier, P. Maierhofer, P. Marquard, M. Steinhauser et al., Precise Charm- and Bottom-Quark Masses: Theoretical and Experimental Uncertainties, Theor. Math. Phys. 170 (2012) 217 [ 1010.6157]

  48. [56]

    Dowdall, C.T.H

    R.J. Dowdall, C.T.H. Davies, R.R. Horgan, G.P. Lepage, C.J. Monahan, J. Shigemitsu et al., Neutral B-meson mixing from full lattice QCD at the physical point, Phys. Rev. D 100 (2019) 094508 [ 1907.01025]

  49. [57]

    Bazavov et al., B- and D-meson leptonic decay constants from four-flavor lattice QCD, Phys

    A. Bazavov et al., B- and D-meson leptonic decay constants from four-flavor lattice QCD, Phys. Rev. D 98 (2018) 074512 [ 1712.09262]

  50. [58]

    Hughes, C.T.H

    C. Hughes, C.T.H. Davies and C.J. Monahan, New methods for B meson decay constants and form factors from lattice NRQCD , Phys. Rev. D 97 (2018) 054509 [1711.09981]

  51. [59]

    ETM collaboration, Mass of the b quark and B -meson decay constants from Nf =2+1+1 twisted-mass lattice QCD , Phys. Rev. D 93 (2016) 114505 [1603.04306]

  52. [60]

    HPQCD collaboration, B-Meson Decay Constants from Improved Lattice Nonrelativistic QCD with Physical u, d, s, and c Quarks , Phys. Rev. Lett. 110 (2013) 222003 [ 1302.2644]

  53. [61]

    Herren and M

    F. Herren and M. Steinhauser, Version 3 of RunDec and CRunDec , Comput. Phys. Commun. 224 (2018) 333 [ 1703.03751]

  54. [62]

    Charles et al.), updated results and plots available at: http://ckmfitter.in2p3.fr, Eur

    CKMfitter Group (J. Charles et al.), updated results and plots available at: http://ckmfitter.in2p3.fr, Eur. Phys. J C41 (2005) 1 [ hep-ph/0406184]

  55. [63]

    Flavour Lattice A veraging Group (FLAG)collaboration, FLAG Review 2024, 2411.04268

  56. [64]

    Bordone, B

    M. Bordone, B. Capdevila and P. Gambino, Three loop calculations and inclusive Vcb, Phys. Lett. B 822 (2021) 136679 [ 2107.00604]

  57. [65]

    MILC collaboration, B→Dℓν form factors at nonzero recoil and |Vcb| from 2+1-flavor lattice QCD , Phys. Rev. D 92 (2015) 034506 [ 1503.07237]

  58. [66]

    HPQCD collaboration, B → Dlν form factors at nonzero recoil and extraction of |Vcb|, Phys. Rev. D 92 (2015) 054510 [ 1505.03925]. 56

  59. [67]

    Fermilab Lattice, MILCcollaboration, Semileptonic form factors for B → D∗ℓν at nonzero recoil from 2 + 1-flavor lattice QCD: Fermilab Lattice and MILC Collaborations , Eur. Phys. J. C 82 (2022) 1141 [ 2105.14019]

  60. [68]

    JLQCD collaboration, B → D∗ℓνℓ semileptonic form factors from lattice QCD with M¨ obius domain-wall quarks, Phys. Rev. D 109 (2024) 074503 [ 2306.05657]

  61. [69]

    BaBar collaboration, Measurement of |Vcb| and the Form-Factor Slope in ¯B → Dℓ−¯νℓ Decays in Events Tagged by a Fully Reconstructed B Meson , Phys. Rev. Lett. 104 (2010) 011802 [ 0904.4063]

  62. [70]

    Belle collaboration, Measurement of the decay B → Dℓνℓ in fully reconstructed events and determination of the Cabibbo-Kobayashi-Maskawa matrix element |Vcb|, Phys. Rev. D 93 (2016) 032006 [ 1510.03657]

  63. [71]

    Belle collaboration, Measurement of the CKM matrix element |Vcb| from B0 → D∗−ℓ+νℓ at Belle , Phys. Rev. D 100 (2019) 052007 [ 1809.03290]

  64. [72]

    Belle collaboration, Measurement of differential distributions of B → D∗ℓ¯νℓ and implications on |Vcb|, Phys. Rev. D 108 (2023) 012002 [ 2301.07529]

  65. [73]

    Belle-II collaboration, Determination of |Vcb| using ¯B0 → D∗+ℓ−¯νℓ decays with Belle II , Phys. Rev. D 108 (2023) 092013 [ 2310.01170]

  66. [74]

    Bernlochner, M

    F. Bernlochner, M. Fael, K. Olschewsky, E. Persson, R. van Tonder, K.K. Vos et al., First extraction of inclusive V cb from q2 moments, JHEP 10 (2022) 068 [2205.10274]

  67. [75]

    M. Kirk, A. Lenz and T. Rauh, Dimension-six matrix elements for meson mixing and lifetimes from sum rules , JHEP 12 (2017) 068 [ 1711.02100]

  68. [76]

    Di Luzio, M

    L. Di Luzio, M. Kirk, A. Lenz and T. Rauh, ∆ Ms theory precision confronts flavour anomalies , JHEP 12 (2019) 009 [ 1909.11087]

  69. [77]

    Lenz and G

    A. Lenz and G. Tetlalmatzi-Xolocotzi, Model-independent bounds on new physics effects in non-leptonic tree-level decays of B-mesons , JHEP 07 (2020) 177 [1912.07621]

  70. [78]

    Albrecht, F

    J. Albrecht, F. Bernlochner, A. Lenz and A. Rusov, Lifetimes of b-hadrons and mixing of neutral B-mesons: theoretical and experimental status , Eur. Phys. J. ST 233 (2024) 359 [ 2402.04224]

  71. [79]

    HPQCD collaboration, Lattice QCD matrix elements for the B0 s − ¯B0 s width difference beyond leading order, Phys. Rev. Lett. 124 (2020) 082001 [ 1910.00970]

  72. [80]

    Fermilab Lattice, MILCcollaboration, B0 (s)-mixing matrix elements from lattice QCD for the Standard Model and beyond , Phys. Rev. D 93 (2016) 113016 [1602.03560]. 57

  73. [81]

    Chakraborty, C.T.H

    B. Chakraborty, C.T.H. Davies, B. Galloway, P. Knecht, J. Koponen, G.C. Donald et al., High-precision quark masses and QCD coupling from nf = 4 lattice QCD, Phys. Rev. D 91 (2015) 054508 [ 1408.4169]

  74. [82]

    Beneke, A Quark mass definition adequate for threshold problems , Phys

    M. Beneke, A Quark mass definition adequate for threshold problems , Phys. Lett. B 434 (1998) 115 [ hep-ph/9804241]

  75. [83]

    Bigi, M.A

    I.I.Y. Bigi, M.A. Shifman, N. Uraltsev and A.I. Vainshtein, High power n of mb in beauty widths and n = 5 → ∞limit, Phys. Rev. D 56 (1997) 4017 [hep-ph/9704245]

  76. [84]

    Czarnecki, K

    A. Czarnecki, K. Melnikov and N. Uraltsev, NonAbelian dipole radiation and the heavy quark expansion , Phys. Rev. Lett. 80 (1998) 3189 [ hep-ph/9708372]

  77. [85]

    M. Fael, K. Sch¨ onwald and M. Steinhauser,Relation between the MS and the kinetic mass of heavy quarks , Phys. Rev. D 103 (2021) 014005 [ 2011.11655]

  78. [86]

    Pineda, Determination of the bottom quark mass from the Υ(1S) system, JHEP 06 (2001) 022 [ hep-ph/0105008]

    A. Pineda, Determination of the bottom quark mass from the Υ(1S) system, JHEP 06 (2001) 022 [ hep-ph/0105008]

  79. [87]

    Nierste, CP asymmetry in flavor-specific B decays , in Proceedings of 39th Rencontres de Moriond on Electroweak Interactions and Unified Theories , pp

    U. Nierste, CP asymmetry in flavor-specific B decays , in Proceedings of 39th Rencontres de Moriond on Electroweak Interactions and Unified Theories , pp. 445–450, 6, 2004 [ hep-ph/0406300]

  80. [88]

    Buras, M.E

    A.J. Buras, M.E. Lautenbacher and G. Ostermaier, Waiting for the top quark mass, K + → π+ν ¯ν, B0 s − ¯B0 s mixing and CP asymmetries in B decays , Phys. Rev. D 50 (1994) 3433 [ hep-ph/9403384]

  81. [89]

    Herrlich and U

    S. Herrlich and U. Nierste, Indirect CP violation in the neutral kaon system beyond leading logarithms, Phys. Rev. D 52 (1995) 6505 [ hep-ph/9507262]

  82. [90]

    Wolfenstein, Parametrization of the Kobayashi-Maskawa Matrix , Phys

    L. Wolfenstein, Parametrization of the Kobayashi-Maskawa Matrix , Phys. Rev. Lett. 51 (1983) 1945

  83. [91]

    Fleischer, M.Y

    J. Fleischer, M.Y. Kalmykov and A.V. Kotikov, Two loop selfenergy master integrals on-shell, Phys. Lett. B 462 (1999) 169 [ hep-ph/9905249]

  84. [92]

    Larin, F.V

    S.A. Larin, F.V. Tkachov and J.A.M. Vermaseren, The FORM version of MINCER,

  85. [93]

    Bekavac, Calculation of massless Feynman integrals using harmonic sums , Comput

    S. Bekavac, Calculation of massless Feynman integrals using harmonic sums , Comput. Phys. Commun. 175 (2006) 180 [ hep-ph/0505174]

  86. [94]

    Baikov and K.G

    P.A. Baikov and K.G. Chetyrkin, Four Loop Massless Propagators: An Algebraic Evaluation of All Master Integrals , Nucl. Phys. B 837 (2010) 186 [ 1004.1153]. 58

  87. [95]

    Weinzierl, Feynman Integrals

    S. Weinzierl, Feynman Integrals. A Comprehensive Treatment for Students and Researchers, UNITEXT for Physics, Springer (2022), 10.1007/978-3-030-99558-4, [2201.03593]

  88. [96]

    Panzer, Algorithms for the symbolic integration of hyperlogarithms with applications to Feynman integrals, Comput

    E. Panzer, Algorithms for the symbolic integration of hyperlogarithms with applications to Feynman integrals, Comput. Phys. Commun. 188 (2015) 148 [1403.3385]

  89. [97]

    Schnetz, Generalized single-valued hyperlogarithms, 2111.11246

    O. Schnetz, Generalized single-valued hyperlogarithms, 2111.11246

  90. [98]

    Duhr and F

    C. Duhr and F. Dulat, PolyLogTools — polylogs for the masses , JHEP 08 (2019) 135 [1904.07279]

  91. [99]

    Borowka, G

    S. Borowka, G. Heinrich, S. Jahn, S.P. Jones, M. Kerner, J. Schlenk et al., pySecDec: a toolbox for the numerical evaluation of multi-scale integrals , Comput. Phys. Commun. 222 (2018) 313 [ 1703.09692]

  92. [100]

    Borowka, G

    S. Borowka, G. Heinrich, S. Jahn, S.P. Jones, M. Kerner and J. Schlenk, A GPU compatible quasi-Monte Carlo integrator interfaced to pySecDec , Comput. Phys. Commun. 240 (2019) 120 [ 1811.11720]

  93. [101]

    Heinrich, S

    G. Heinrich, S. Jahn, S.P. Jones, M. Kerner, F. Langer, V. Magerya et al., Expansion by regions with pySecDec , Comput. Phys. Commun. 273 (2022) 108267 [2108.10807]. 59

Pith tools

Reviewed August 7, 2026 · model on record in the stance chip above.